Mississippian Culture Begins

Around 950 AD, communities in the Mississippi River valley began to develop a new way of organizing society, one that would reshape much of eastern North America. Archaeologists call it the Mississippian culture. Its best-known center, Cahokia, near modern St. Louis, Illinois, grew into the largest city north of Mexico before European contact. The event's listing under Mexico in the record is an error of geography: Mississippian sites lie in the central and southeastern United States, though the culture's rise is sometimes discussed alongside the wider traditions of Mesoamerica.

The background lies in the earlier Woodland period, when peoples of the Midwest and South built burial mounds, traded widely, and gathered seasonal harvests. Over time, farming of maize, along with beans and squash, became more important, and it supported denser populations in the fertile river floodplains. Maize agriculture did not arrive overnight, and scholars debate how quickly and in what ways it transformed local societies. Around the tenth and eleventh centuries, people in the region began to settle in larger permanent towns centered on plazas and earthen platform mounds.

Cahokia's rise is usually placed around 1050, with growth that appears unusually rapid. Its core featured Monks Mound, a massive earthen platform that is among the largest prehistoric earthworks in the Americas, rising in several terraces above a great plaza. Surrounding it were hundreds of smaller mounds, residential neighborhoods, and a wooden post circle often called Woodhenge, which may have tracked the movement of the sun through the seasons. Population estimates for the city and its immediate surroundings at its height vary, with figures of roughly 10,000 to 20,000 commonly cited. The city drew people from the wider region and traded for goods such as copper, shells, and stone from distant places.

Mississippian societies were typically led by chiefs or elites whose authority was tied to religion, ancestry, and control of ceremony. Shared symbols appear across many sites, including motifs of birds, warriors, and sky and underworld imagery, which scholars group under the label Southeastern Ceremonial Complex. Whether Cahokia had direct links with Mesoamerican peoples is uncertain; similarities in some practices have been noted, but evidence for direct contact is thin.

Cahokia declined from about 1200 and was largely abandoned by around 1350. Explanations include flooding, environmental stress, resource depletion, political unrest, and shifting social loyalties, and no single cause is accepted. Mississippian traditions continued elsewhere, and later peoples of the Southeast, including ancestors of groups such as the Natchez, maintained related societies into the era of European contact. Today Cahokia Mounds is a UNESCO World Heritage Site, valued as evidence of complex urban life in North America long before Columbus.